Pen Park Hole

The cave was discovered by quarrying in or shortly before 1669 - its discovery was considered important enough to inform King Charles II, it was at the King's request that Captain Samuel Sturmy entered the hole and underground cave. Captain Sturmy descended into the pit on July 2, 1669. Having roped down from an old lead mine, he and a miner companion descended using 150 ft of rope. They found a large chamber which they illuminated with candles. Exploring further they found an underground river 120 ft wide. Seeing a passage 30 ft above them, they had a ladder lowered which they used to ascend into the passage. Here they found what they thought was a rich mine "an abundance of strange…

The cave consists of some short climbs, and a few chambers, the last of which is a very tall rift chamber with a lake that changes height by as much as 20 metres. Side passages contain impressive dogtooth spar. The cave was formed by rising geothermal water (and is one of the best examples of a hydrothermal cave in the UK or Ireland), making it far older than other caves in the area, at around 190 million years old. The main chamber is 68 m high, 30 m long and 15 m wide. The lake within it is 15 m deep but the level fluctuates widely. The cave entrance is in a residential area and is protected by a steel plate for safety reasons. Access is under the control of Bristol City Council.